Molecular Basis of Cerebral Vasospasm: What Can We Learn from Transcriptome and Temporal Gene Expression Profiling in Intracranial Aneurysm?

Cerebral vasospasm (CV) is a significant complication following aneurysmal subarachnoid hemorrhage (aSAH), and lacks a comprehensive molecular understanding. Given the temporal trajectory of intracranial aneurysm (IA) formation, its rupture, and development of CV, altered gene expression might be a molecular substrate that runs through these clinical events, influencing both disease inception and progression. Utilizing RNA-Seq, we analyzed tissue samples from ruptured IAs with and without vasospasm to identify the dysregulated genes. In addition, temporal gene expression analysis was conducted. We identified seven dysregulated genes in patients with ruptured IA with vasospasm when compared with those without vasospasm. We found 192 common genes when the samples of each clinical subset of patients with IA, that is, unruptured aneurysm, ruptured aneurysm without vasospasm, and ruptured aneurysm with vasospasm, were compared with control samples. Among these common genes, TNFSF13B, PLAUR, OSM, and LAMB3 displayed temporal expression (progressive increase) with the pathological progression of disease that is formation of aneurysm, its rupture, and consequently the development of vasospasm. We validated the temporal gene expression pattern of OSM at both the transcript and protein levels and OSM emerges as a crucial gene implicated in the pathological progression of disease. In addition, RSAD2 and ATP1A2 appear to be pivotal genes for CV development. To the best of our knowledge, this is the first study to compare the transcriptome of aneurysmal tissue samples of aSAH patients with and without CV. The findings collectively provide new insights on the molecular basis of IA and CV and new leads for translational research.

TIMP1 is an early biomarker for detection and prognosis of lung cancer

BACKGROUND

Lung cancer remains the major cause of cancer-related deaths worldwide. Early stages of lung cancer are characterized by long asymptomatic periods that are ineffectively identified with the current screening programs. This deficiency represents a lost opportunity to improve the overall survival of patients. Serum biomarkers are among the most effective strategies for cancer screening and follow up.

METHODS

Using bead-based multiplexing assays we screened plasma and tumours of the KrasG12D/+; Lkb1f/f (KL) mouse model of lung cancer for cytokines that could be used as biomarkers. We identified tissue inhibitor of metalloproteinase 1 (TIMP1) as an early biomarker and validated this finding in the plasma of lung cancer patients. We used immunohistochemistry (IHC), previously published single-cell RNA-seq and bulk RNA-seq data to assess the source and expression of TIMP1in the tumour. The prognostic value of TIMP1 was assessed using publicly available human proteomic and transcriptomic databases.

RESULTS

We found that TIMP1 is a tumour-secreted protein with high sensitivity and specificity for aggressive cancer, even at early stages in mice. We showed that TIMP1 levels in the tumour and serum correlate with tumour burden and worse survival in mice. We validated this finding using clinical samples from our institution and publicly available human proteomic and transcriptomic databases. These data support the finding that high tumour expression of TIMP1 correlates with an unfavorable prognosis in lung cancer patients.

CONCLUSION

TIMP1 is a suitable biomarker for lung cancer detection.

Functionally enhanced cell spheroids for stem cell therapy: Role of TIMP1 in the survival and therapeutic effectiveness of stem cell spheroids

Stem cell therapy has emerged as a promising regenerative medicine strategy but is limited by poor cell survival, leading to low therapeutic outcomes. We developed cell spheroid therapeutics to overcome this limitation. We utilized solid-phase FGF2 to form functionally enhanced cell spheroid-adipose derived (FECS-Ad), a type of cell spheroid that preconditions cells with intrinsic hypoxia to increase the survival of transplanted cells. We demonstrated an increase in hypoxia-inducible factor 1-alpha (HIF-1α) levels in FECS-Ad, which led to the upregulation of tissue inhibitor of metalloproteinase 1 (TIMP1). TIMP1 enhanced the survival of FECS-Ad, presumably through the CD63/FAK/Akt/Bcl2 anti-apoptotic signaling pathway. Cell viability of transplanted FECS-Ad was reduced by TIMP1 knockdown in an in vitro collagen gel block and a mouse model of critical limb ischemia (CLI). TIMP1 knockdown in FECS-Ad inhibited angiogenesis and muscle regeneration induced by FECS-Ad transplanted into ischemic mouse tissue. Genetic overexpression of TIMP1 in FECS-Ad further promoted the survival and therapeutic efficacy of transplanted FECS-Ad. Collectively, we suggest that TIMP1 acts as a key survival factor to improve the survival of transplanted stem cell spheroids, which provides scientific evidence for enhanced therapeutic efficacy of stem cell spheroids, and FECS-Ad as a potential therapeutic agent to treat CLI. STATEMENT OF SIGNIFICANCE: We used FGF2-tethered substrate platform to form adipose-derived stem cell spheroids, as we named as functionally enhanced cell spheroid-adipose derived (FECS-Ad). In this paper, we showed that intrinsic hypoxia of spheroids upregulated expression of HIF-1α, which in turn upregulated expression of TIMP1. Our paper highlights TIMP1 as a key survival factor to improve survival of transplanted stem cell spheroids. We believe that our study has a very strong scientific impact as extending transplantation efficiency is essential for successful stem cell therapy.

Regulation of Inflammatory Responses by Oncostatin M

Oncostatin M (OM) is a pleiotropic cytokine produced late in the activation cycle of T cells and macrophages. In vitro it shares properties with related proteins of the IL-6 family of cytokines; however, its in vivo properties and physiological function are as yet ill defined. We show that administration of OM inhibited bacterial LPS-induced production of TNF-α and lethality in a dose-dependent manner. Consistent with these findings, OM potently suppressed inflammation and tissue destruction in murine models of rheumatoid arthritis and multiple sclerosis. T cell function and Ab production were not impaired by OM treatment. Taken together these data indicate the activities of this cytokine in vivo are antiinflammatory without concordant immunosuppression.

Oncostatin M Up-Regulates Tissue Inhibitor of Metalloproteinases-3 Gene Expression in Articular Chondrocytes via De Novo Transcription, Protein Synthesis, and Tyrosine Kinase- and Mitogen-Activated Protein Kinase-Dependent Mechanisms

Cytokines and growth factors regulate physiologic and pathologic turn-over of cartilage extracellular matrix (ECM) by altering the balance between tissue inhibitors of metalloproteinases (TIMPs) and matrix metalloproteinases (MMPs). Oncostatin M (OSM) is a cytokine of the IL-6 family whose levels are increased in the serum and synovial fluids of patients with rheumatoid arthritis. We examined responsiveness of the TIMP-3 gene to OSM in articular chondrocytes and studied the regulatory and signaling mechanisms of this response. OSM induced TIMP-3 mRNA and protein expression in a dose- and time-dependent fashion. Concomitantly, stromelysin-1 and collagenase-1 RNA and activities were also induced. A cartilage matrix growth factor, TGF-β, induced TIMP-3, but combined OSM and TGF-β did not further increase the extent of induction, suggesting a lack of synergy between the two. OSM induction of TIMP-3 gene expression was dependent upon de novo protein synthesis and transcription. RNA decay time-courses suggested that the OSM-mediated increase of TIMP-3 RNA was not due to enhanced message stability and, along with inhibition by actinomycin-D, suggested a transcriptional control. The antiinflammatory glucocorticoid, dexamethasone, down-regulated this augmentation. Investigation of the signaling mechanisms revealed that protein tyrosine kinase inhibitors genistein and herbimycin A, as well as the specific mitogen-activated protein kinase (MAPK) kinase inhibitor PD98059, suppressed OSM-induced TIMP-3 message expression, suggesting the involvement of tyrosine kinases and mitogen-activated protein kinase cascades in the signaling of OSM leading to TIMP-3 RNA enhancement. Thus OSM can potentially alter the cartilage matrix metabolism by regulating genes like TIMP-3 and matrix metalloproteinases.